Development of spectrophotometric methods for the analysis of functional groups in oxidized organic aerosol

Abstract

Spectrophotometric methods were developed to quantify carbonyl, hydroxyl, carboxyl, and ester groups in samples with composition typical of oxidized atmospheric organic aerosol. The methods employ derivatizing agents to convert functional groups to characteristic colored derivatives that are quantified by spectrophotometry. Effects of molecular structure on quantification have been evaluated by measuring calibration curves for a variety of monofunctional and multifunctional compounds. In addition, potential interferences from compounds containing nontarget functional groups have been determined and methods developed to eliminate these interferences. Detection limits are approximately 0.01, 0.02, 0.03, and 0.1 μmoles for carbonyl, hydroxyl, carboxyl, and ester groups, respectively. The use of these methods for analysis of secondary organic aerosol (SOA) composed of a complex mixture of oxidized compounds is also demonstrated. © 2013 American Association for Aerosol Research.